Freund’s adjuvant may be used to form water-in-oil emulsions with antigens for the injection of immunogens for antibody production. Proper emulsion formation is essential and should be tested by observing a drop of the emulsion on the surface of water which should 'bead and not disperse. Antigens properly emulsified stimulate a strong and long-lasting immune response due to the slow release of antigen into the host’s system.